[填空题]Like all animal species, plant species must spread their offspring to suitable areas
where they can grow and pass on their parent’s genes. Young animals generally spread by (1) ______
walking or flying. Because plants don’t have that ability, they may somehow hitchhike. (2) ______
Some plant seeds scatter by blowing in the wind or floating on water. Many other plant
species, though, trick an animal into carrying their seeds. How do they do They enclose
them within a tasty fruit and advertise the fruit’ s ripeness by its color or smell. The hungry
animal collects and swallows the fruit, walks or flies off, but later spits out the seeds some- (3) ______
where far from its parent tree. Seeds can thereby be carried thousands of mi]es. It may (4) ______
surprise you to learn that plant seeds can resist digestion. In fact, some seeds actually
require passage through an animal’ s body before they can grow. Wild strawberries offer a
goo